This invention relates to the manufacture of hybrid substrates and more particularly to method for separating leaded hybrid substrates from carrier support plates following a reflow solder operation.
Electrical components are permanently electrically connected in thick film hybrid circuits by locating the flat bottoms of hybrid substrates carrying circuit patterns and components on a conveyer belt that moves them through a reflow solder operation. In order to simultaneously connect the components and tines of leads into a hybrid circuit, the flat bottom of a hybrid substrate is flush mounted on the flat top of a thin aluminum support plate or carrier, with tines on the substrate bottom offset from the carrier. During the subsequent reflow solder operation, solder flux associated with the tines melts and flows along the bottom of the substrate and into the opening between it and the carrier plate. As the stacked substrate and plate move away from the heat zone in the reflow solder operation, the melted solder begins to solidify. This causes a substrate and associated carrier plate to stick together. If these parts are allowed to cool such that the solder flux solidifies into a paste, it is extremely difficult to separate them. Although stacked substrates and carriers may be passed directly from a reflow solder operation to a cleaning and defluxing operation, it has been found that many of the cleaned parts are still stuck together. A human operator must then pry each substrate from the associated carrier and again pass them through a cleaning and defluxing operation. Since this hand operation must be performed on individual substrates, it is time consuming and expensive. An object of this invention is the provision of machine operated method for separating hybrid substrates from associated carrier plates following a reflow solder operation.